1. Field of the Invention
This invention relates to a send-out system for recording/reproduction enabling plural recording/reproducing apparatus having different bit rates to be used for reciprocal signal exchange.
2. Description of the Prior Art
As systems digitizing and recording video signals, there are currently known a digital video tape recorder of a so-called D1-format (D1VTR) and a digital video tape recorder of a D2-format (D2VTR).
With the D1VTR, recording and/or reproduction is performed with 10-bit-per-sample luminance data Y, obtained on sampling luminance signals Y at a sampling frequency of 13.5 MHz, and with 10-bit-per-sample first and second chroma (chrominance) data C.sub.1, C.sub.2, obtained on sampling color difference signals R-Y and B-Y with a sampling frequency of 6.75 MHz, respectively, as video data.
With the above D1VTR, the luminance data Y with the bit rate of 13.5 MHz/10 bits and the chroma data C.sub.1, C.sub.2 with the bit rate each of 6.75 MHz/10 bits, that is component data, are transmitted via serial interface as 270 MB/sec serial data.
With the D2VTR, video data are recorded and/or reproduced as the 10-bit-per-sample composite data, obtained upon sampling composite video signals with a sampling frequency of 14.3 MHz.
The D2VTR transmits the composite data with the bit rate of 14.3 MHz/10 bits via a serial interface as 143 MB/sec serial data.
The D1VTR and D2VTR, capable of assuring a high picture quality, are in current use mainly in broadcasting stations.
In keeping with the users' propensity towards AV in recent years, development of a widescreen video tape recorder (widescreen VTR), in which only the aspect ratio of the NTSC system, the standard system adopted in Japan, is changed from 4:3 to 16:9 in recording and/or reproduction, is proceeding, as for example in EDTV2 (extended or high definition television 2).
With the widescreen VTR, recording and/or reproduction is performed with 10-bit-per-sample luminance data, obtained on sampling luminance signals Y at a sampling frequency of 18 MHz, and with 10-bit-per-sample first and second chroma (chrominance) data C.sub.1, C.sub.2, obtained on sampling color difference signals R-Y and B-Y each with a sampling frequency of 9 MHz, respectively, as video data.
With the widescreen VTR, the luminance data with the bit rate of 18 MHz/10 bits and the chroma data C.sub.1, C.sub.2 with the bit rate each of 9 MHz/10 bits, that is component data, are transmitted via serial interface as 360 MB/sec serial data.
As may be seen from above, recording/reproducing apparatus with various bit rates are in current use. It may be predicted that recording/reproducing apparatus having bit rates different from those of the above recording/reproducing apparatus may be developed in future.
Should the recording/reproducing apparatus having different bit rates be used in future, it may be desirable to exchange video data between recording/reproducing apparatus having different bit rates, as when the video data reproduced from a D1VTR is desired to be recorded on D2VTR. In such case, the bit rate may be changed by a rate converter for converting the 270 MB/sec video data into 143 MB/sec video data or a masking circuit for converting 360 MB/sec video data into 143 MB/sec video data. It is desired to use these rate converting means integrally to enable video data to be exchanged between the recording/reproducing apparatus with different bit rates.